If you've never divided your Daylilies before, don't worry, it's simple enough to do. They should be divided every 3 to 5 years, preferably in late summer.
Like everything else about Daylilies, division is very simple! Just dig up the plant, taking care to keep as many of the roots intact as possible. Then plunge two garden forks back-to-back through the center of the plant and gently pull them apart, dividing the plant in two. Repeat this until you have smaller clumps. Trim the foliage back to about 12 inches and re-plant the new clumps, hilling up the soil and fanning at the roots.
It's truly as simple as that! You'll soon be enjoying even more of your favorite Daylilies, and if you're looking for a great companion plant, try mixing them with Irises. They both appreciate sunshine and good drainage, and bloom successively, with the Daylilies often encoring to keep the Irises company!